Public water system · IA5358096
ActiveOnslow Water Supply
At a glance
Onslow Water Supply (PWSID IA5358096) is an active community water system in Jones County, Iowa. It reports serving 201 people through 110 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in January 2022.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
201
Service connections
110
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Onslow Water Supply compare with other water systems in Jones County?
By EPA's size categories, Onslow Water Supply is a very small system (500 people or fewer). Jones County has 37 active public water systems. Its population served is about half of the county average of 435 people per system, and accounts for 1.3% of the 16,079 people reported by systems filed under the county. Across Iowa, the 1,828 active systems average 1,718 people each. Nationally, the average active community water system reports serving 6,703 people, so Onslow Water Supply is well below that figure.
What does “community water system” mean?
A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. Iowa has 1,084 active community water systems, 59% of the state's 1,828 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 1,502 Iowa systems (82%) list groundwater as their primary source.
Who owns and regulates Onslow Water Supply?
EPA lists Onslow Water Supply as owned by a local government. The IA state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 10 of the 37 active systems in Jones County (27%) are also owned by a local government.
Does Onslow Water Supply have drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in January 2022. The violations listed here began between April 1995 and January 2022. By type: 8 monitoring and reporting and 4 public notice, recordkeeping or other. The contaminant or rule involved most often is Consumer Confidence Rule (4 of them). EPA lists 12 as resolved. Resolved means at least one resolving action is on record: the system returned to compliance, the rule no longer applies, or no further action was needed.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2022-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2019-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2017-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2013-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2012-06-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2002-07-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2000-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 1999-10-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1996-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 1996-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,2,4-Trichlorobenzenecode 2378 | No | Resolved |
| 1995-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 1995-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Lindane (gamma-BHC)code 2010 | No | Resolved |
The 12 most recent violations in EPA's records, newest first.Labels and codes come from EPA's SDWIS reference tables. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found. "Health-based" marks violations of a legal limit or required treatment.
Onslow Water Supply: frequently asked questions
Who runs Onslow Water Supply?
Onslow Water Supply (PWSID IA5358096) is a community water system owned by a local government. It is regulated by the IA state drinking water program.
How many people does Onslow Water Supply serve?
Onslow Water Supply reports serving 201 people through 110 service connections in Jones County, Iowa.
Where does Onslow Water Supply get its water?
EPA SDWIS lists this system's primary water source as groundwater. Groundwater means the system draws its water from wells or springs fed by underground aquifers.
Does Onslow Water Supply have any drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in January 2022. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found.
Is Onslow Water Supply's water safe to drink?
AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in January 2022. For current results, consult the system's annual water quality report, EPA ECHO, or the IA state drinking water program.
Where can I find Onslow Water Supply's water quality report?
As a community water system, Onslow Water Supply must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.
Other water systems in Jones County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Anamosa Municipal Water Supply | Jones | 4,457 | Community | Groundwater |
| Monticello Water Supply | Jones | 4,040 | Community | Groundwater |
| Anamosa State Penitentiary | Jones | 1,230 | Community | Groundwater |
| Caseys General Store (Anamosa) | Jones | 1,215 | Transient non-community | Groundwater |
| Olin Water Supply | Jones | 651 | Community | Groundwater |
| Wyoming Water System | Jones | 523 | Community | Groundwater |
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About this data
Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.
Cite as: AquaCensus, “Onslow Water Supply, PWSID IA5358096, Iowa”, https://aquacensus.com/water-systems/iowa/onslow-water-supply-ia5358096 (data as of October 1, 2026).